100m Simple FM Transmitter

---

Here is a very interesting and simple FM transmitter used to transmit audio in the wide range up to 100M using only one transistor. The entire circuit of FM transmitter is divided into three major stages oscillator, modulator and amplifier. The transmitting frequency of 88-108 MHz is generated by adjusting VC1. The input audio generated by microphone is changed into electric signal and is given to base of transistor T1. Transistor T1 is used as oscillator which oscillates the frequency of 88-108 MHz. The oscillated frequency depends upon the value R2, C2, L2 and L3. Transmitted audio from FM transmitter circuit can be received by standard FM receiver. 

 PARTS LIST

Resistors (all ¼-watt, ± 5% Carbon)
R1 = 180 KΩ
R2 = 10 KΩ
R3 = 15 KΩ
R4 = 4.7 KΩ

Capacitors
C1 = 10 KPF
C2 = 10 PF
C3 = 20 KPF
C4 = 0.001 µF
C5 = 1 µF/10V
C6 = 4.7 PF
C7 = 10 KPF
C8 = 3.3 PF
VC1 = 22 PF

Semiconductor
T1 = BF194B

Miscellaneous
MIC1 = Condenser mike
L1, L2 = 3 turns of 22 SWG wire around any thin pencil
L3 = 2 turns of 22 SWG wire around any thin pencil.